I'm Robert Siegel and we begin the hour with the mystery that has confounded the world for three days. What happened to Malaysia Airlines Flight 370? The plane disappeared Friday on its way from Malaysia to Beijing with 239 people aboard. Today, the search widened. Aircraft and ships from Malaysia, Vietnam, China and the United States are searching the South China Sea for any sign.

For more on this story, we turn to NPR's Frank Langfitt in Shanghai. And Frank, the whole weekend has gone by. Still nothing?

FRANK LANGFITT, BYLINE: Practically nothing, Robert. You know, we're saying the plane disappeared over the Gulf of Thailand. There were more than 70 ships and aircraft and personnel from 10 countries, including China, Vietnam and Malaysia. But they haven't been able to find anything. There's no debris field, which is generally what you might find with an explosion. They did find an oil slick, but it turned out to be shipping oil.

It is very unusual, as you know, a plane to disappear at 35,000 feet. This is generally the safest time of a flight. There's some theories, but they're pretty vague. Hijacking, maybe a mid-air breakup, perhaps an explosion, but honestly, it seems like they're really grasping at things right now.

SIEGEL: Now, there were two passengers on board, apparently traveling with stolen passports. What's been learned about them since the plane disappeared?

LANGFITT: Well, Malaysian officials talked about them today. They did not provide identities. They said they did not look Asian and implied that they were both black. They said the resembled, and this is a little bit odd, Mario Balotelli, I think I'm pronouncing his name correctly. He's a famous black soccer player from Italy. The pair were traveling from Malaysia through Beijing, onto Amsterdam and then to separate destinations in Europe.

And they were traveling on passports that were reported stolen in the past couple of years from European tourists in the island resort of Phuket.

SIEGEL: Any idea of how the travelers obtained these passports?

LANGFITT: Well, it wouldn't have been very hard. Thailand has a huge stolen passport and fake document industry. From what I've read, a good stolen passport, fake passport costs about $900. What's more interesting is how they got the airline tickets. The Financial Times talked to a travel agent in Thailand who bought the tickets for them and she said she purchased them on behalf of an Iranian middleman who she'd known for years and that they just wanted a cheap flight to Europe.

They didn't care about the itinerary. And this sort of suggests that maybe there's nothing targeted about the trip, they were just trying to get to Europe. Also, the authorities really emphasized that they're not connecting the pair to the plane's disappearance, but obviously they're investigating because of the passports.

SIEGEL: Yes. We don't know that these two travelers had anything to do with the disappearance of the aircraft, but it does seem to be a critical question, how these two men got on the plane.

LANGFITT: Yeah, this is really fascinating, Robert. Interpol, of course, has a database of stolen passports and these passports that they guys were using - one was an Italian passport, the other Austrian - were in the database. But Interpol says that Malaysia didn't even check the database. The United States and the United Kingdom do check this database, but Interpol says most countries actually don't and they said it's a gaping loophole in airline safety.

And Interpol was actually very critical over the weekend. Interpol Secretary General Ronald Noble said, quote, "For years, Interpol has asked why should countries wait for a tragedy to put prudent security measures in place?" And Noble says, some countries cite privacy concerns or lack of resources for not checking the database, but he says this is really good example of why more countries should do so.